Lighting systems for public roadways, thoroughfares, and facilities, private and commercial facilities, including industrial plants, office-building complexes, schools, universities, and other such organizations, and other public and private facilities account for enormous yearly expenditures of energy and financial resources, including expenditures for lighting-equipment acquisition, operation, maintenance, and administration. Because of rising energy costs, falling tax-generated funding for municipalities, local governments and state governments, and because of cost constraints associated with a variety of different enterprises and organizations, expenditures related to acquiring, maintaining, servicing, operating, and administering lighting systems are falling under increasing scrutiny. As a result, almost all organizations and governmental agencies involved in acquiring, operating, maintaining, and administering lighting systems are seeking improved methods and systems for control of lighting fixtures in order to lower administrative, maintenance, and operating costs.